1. Field of the Invention
This invention relates to surface active agents and, more particularly, to surface active agents based upon polypeptides.
2. Description of the Prior Art
Surface active agents (surfactants) such as soaps, detergents and the like have broad utility in the industrial and cosmetic fields. These surface active agents form the basis, in the cosmetic field, for shampoos, hand soaps and the like. When surface active agents are used in cosmetic applications, it is necessary that they exhibit minimum dermatological irritation so as not to cause rashes, allergic reactions and the like to the user of such products.
It has been recognized that proteins are very useful in many cosmetic applications and those which are in substantially pure form have remedial effects upon skin. Thus, it has been proposed to provide surface active agents for use in shampoos and soaps which are based upon proteins. To this end, surface active agents have been proposed which are based upon polypeptides. For example, fatty acid chlorides have been reacted with protein hydrolyzates to form salts which act as surface active agents. In addition, proteins have been thermally condensed with amines in water and also condensed with alkanol amines followed by acylation with fatty acids in order to produce such surface active agents based upon proteins.
Although these prior art approaches have met with some degree of success, such approaches have the disadvantage of either having a relatively high level of skin irritation and/or being prohibitive from a cost point of view.
One particularly useful surface active agent used in shampoos and the like is dodecylbenzene sulfonic acid. This particular surface active agent has been shown to be useful as a shampoo but has the disadvantage of having a relatively high level of skin irritation.
In accordance with the present invention, a surface active agent based upon polypeptides, i.e. proteins, is provided which is low in cost, provides minimal skin and eye irritation, while providing recognized advantages which proteins have upon the skin.